Method and device for producing products in web form

ABSTRACT

This invention pertains to methods and devices for producing products in web form. In particularly advantageous embodiments, the instant invention relates to methods and devices for forming films by coating a coating mass formed from organic raw materials in an aqueous basis onto a reusable transfer support web to form a composite. The composite is then dried and the dried coating transferred onto a intermediate support material. The dried coating and intermediate support material are directed to a winding station. Upon separation from the dried coating, the dried reusable transfer support web may be directed to treatment and cleaning stations and is subsequently reused.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is being filed under rule 1.371 National StageApplication of pending International Application No. PCT/EP03/00334,filed Jan. 15, 2003, which claims priority to the following provisionalapplication: U.S. Patent Application No. 60/351,745, filed Jan. 25,2002.

FIELD OF THE INVENTION

The present invention pertains to a method and a device for producingproducts in web form, in particular, thin films by coating a coatingmass comprising organic raw materials in an aqueous basis on a reusablesupport web, drying the products and transferring the dried productsonto a reusable intermediate support material.

BACKGROUND OF THE INVENTION

Flat administration forms to be applied in the oral region and on mucousmembranes of the mouth are known. U.S. Pat. No. 3,444,858 describesmedicament strips based on a gelatin-like material. Also, pharmaceuticalproducts in the form of a film have already been described in the early70 s. DE-A 24 49 865 described medicinal active substance carriers inthe form of a film, containing different active substances and activesubstance concentrations.

U.S. Pat. No. 4,128,445 discloses technical solutions in loading ofcarrier material with active substances and, in this context, goes intothe subsequent addition of active substance preparations by applyingthem onto pre-fabricated film-shaped preparations. The documentdescribes loading methods in dry and moist form aiming at achieving auniform, subsequent distribution of active substance on a layer.

Canadian patent application No. 492 040 describes a process formanufacture of film-shaped preparations employing active substance alongwith gelatin, agar, gluten, carboxyvinyl polymer, polyhydric alcohol,vegetable mucilage, wax or water.

Also known are proposals for application of active substance-loadedfilms or foils outside the pharmaceutical field. Thus, in EP-A 219 762 awater-soluble film of starch, gelatin, glycerol or sorbite is disclosed,which is coated using the roll coating method. In this connection, it isstated that such dosing forms may also be produced employing ingredientsof chemical reagents, aromatics and the like.

DE-A 36 30 603 provides for a flat dosage form, on a carrier material(release film), to be peelable in doses.

Drug containing film-shaped systems and their advantages are furtherknown from U.S. Pat. No. 5,047,244. These systems comprise adouble-layered structure of a water swellable layer and anon-water-swellable barrier film. The use of polymers such aspolyethylene glycol, the use of colloidal silicon dioxide, ofbioadhesive (e.g. carboxy-functional) polymers, but also of polyvinylalcohol, and of a number of other auxiliary substances is likewise knownfrom the above publication.

A preparation suitable for making film-shaped aromatics-containingpreparations is described by EP-A 460 588. A composition comprising 20to 60 weight-% of film former, 2 to 40 weight-% of gel former, 0.1 to 35weight-% of active substance or aromatic, and a maximum of 40 weight-%of an inert filling agent is regarded as affording particularadvantages. As a gel former, polyvinyl alcohol is mentioned besidesother ingredients. However, as it turns out, the gel-forming propertiesof polyvinyl alcohol are only partially compatible with the film formersmentioned in this written document. A portion of 20 weight-%, and more,of film-former—mostly a sugar derivative, polyethylene glycol, etc.—leadto considerable loss of aroma occurring already in thin layer drying,which is part of the production process.

The films or coatings to which the instant invention is related arebased on organic raw materials or on a mix of such substances. These arepreferably water-soluble substances. Such organic raw materials includepolymers such as polyvinyl alcohol, polyvinyl pyrrolidone, cellulosederivatives, polyvinyl acetate, polyetlylene glycol, alginate,carrageenan, xanthan, gelatine and other water-soluble polymers known tothe skilled artisan, as well as mixtures and copolymers of suchsubstances. If desired, such films or coatings may also include fillerssuch as mannitol, lactose, calcium phosphate, glucose, sorbitol etc.,active substances such as drugs, aroma substances, menthol etc.,sweeteners such as cyclamate, flavours such as glutamate, and otheringredients, including in some cases volatile ingredients. These filmsmay also have mucoadhesive properties.

Usually, the films and coatings are produced by means of casting methodsor reverse coating methods. The manufacture of thin films or coatings isaccomplished according to the present invention in that initially acoating mass is prepared containing organic substances which aresuitable for forming a film, or a coating, for instance, polymers suchas polyvinyl alcohol, polyvinyl pyrrolidone, cellulose derivatives,polyvinyl acetate, polyetlylene glycol, alginate, carrageenan, xanthan,gelatine and other water-soluble polymers known to the skilled artisan,as well as mixtures or copolymers of such substances. Preferably, thesesubstances are completely or partially dissolved or dispersed in water.Apart from water, other solvents may be used as well, e.g. alcohols suchas methanol, ethanol, propanol or solvent mixtures such as water-alcoholmix.

The coating composition may further comprise various additives, e.g.fillers such as mannitol, lactose, calcium phosphate, glucose, sorbitoletc., and/or active substances such as drugs, aroma substances, mentholetc., and/or sweeteners such as cyclamate, flavours such as glutamate,and other ingredients, including in some cases volatile ingredients.

The coating mass thus obtained is subsequently applied to a web-shapedsupport material, using the casting method or reverse coating method. Assupport material, a web or sheet of paper, plastic, metal or a compositeof two or more of these materials may be used.

The product web may, for example, have a width of about 0.1 m to about 2m. Preference is given a width in the range of from 0.5 to 1.6 m. Thefilms or coatings applied to the support layer are preferably thin, thatmeans, their thickness ranges of from about 10 to 500 μm, preferablyfrom 50 to 200 μm.

The coated support material, i.e. the composite of support and coatingcomposition, is thereafter transferred into a drying device (dryingoven) and transported through the same, preferably continuously.

The dried composite is then wound up and stored.

The above-described method, however, has the disadvantage that parts ofthe active-ingredient diffuse from the coating into the support materialduring the contact period. For that reason, used support material cannotbe used again for the preparation of the same or other products in webform, since an unpredictable quantity of active-ingredient disappearsfrom the coating or diffuses back from the support material into thecoating during the contact period. Thus, big amounts of waste supportmaterial arise during the conventional process making the preparationexpensive and environmentally less favourable.

SUMMARY OF THE INVENTION

The object of the present invention was to provide a method and a devicefor the preparation of products in web form in which reduced amount ofwaste transfer film occurs, thus, saving costs and environmental effort,as well.

The invention, accordingly, pertains to a method for producing productsin web form in which a coating mass first is applied onto the surface ofa transfer support web, subsequently the composite of coating mass andtransfer support web is dried thermally, then an intermediate supportmaterial is applied on the surface of the coating and finally thecomposite of the intermediate support material and the coating isseparated from the transfer support web, wound up and stored, whereinthe transfer support web used is preferably an endless loop.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a side view of an exemplarymachine in accordance with the invention.

DETAILED DESCRIPTION OF THE INVENTION

In the preferred embodiment of the present invention, the transfersupport web is comprised of a solid material such as polymer materialhaving sufficient mechanical strength and heat resistance or thetransfer film is comprised of a composite material of paper with apolymer layer on top or a metal foil or a composite material of metaland polymer film such as metallized polymer film.

The endless loop used as the transfer support web in the presentinvention, preferably, has a uniform thickness over its total length toavoid fluctuations in the thickness of the product in web form appliedthereon.

The composite of the coating and the transfer support web is dried bythermal treatment in a heating device, preferably in a hot air chamberat temperatures in the range of from 40 to 120° C., preferred from 50 to100° C. It is also possible to conduct the thermal treatment in multiplesteps through multiple heating devices at different temperatures. Thetotal time period for thermal treatment lies within the range of from 5s to 60 s, preferably from 10 s to 50 s.

After the thermal treatment, the humidity of the product in web form isadjusted in the appropriate range of from about 20 to 60%. The compositeis then fed to a laminating- or cooling device, where an intermediatesupport material coming from a storage roll is applied onto the coating.The intermediate support material is preferably fixed with a strip of anadhesive at the starting point. Possible adhesives are hot meltadhesives or pressure sensitive adhesives which are commerciallyavailable. The laminating- or cooling device comprises essentially acooling drum on which the laminate of intermediate support material,coating and transfer support web is pressed together to maintain asufficient connection.

The intermediate support material may be comprised of paper or paperlike material like cardboard, however, it is also possible to usepolymer films as intermediate support material.

Leaving the laminating station the transfer support web is separatedfrom the laminate of intermediate support material, coating and transfersupport web by means of rolls. The separation of the transfer supportweb is easy, if the humidity of the coating is adjusted in theappropriate range.

The ready prepared product in web form comprising the intermediatesupport material and the coating is wound up and stored for its finaldestination subsequently after its separation from the transfer supportweb.

The separated transfer support web, however, is fed to a regenerationstation. The regeneration of the transfer support web comprises at leastmechanical removal of every adhering foreign particles and vacuumcleaning of the mechanical treated transfer support web. Additionally,the regeneration can be combined with a wet or chemical decontaminationcomprising washing the transfer support web with clear water or organicsolvent or cleaning it with detergents and subsequent drying in hot air.In any case, the regenerated transfer support web is wound up and fedback or alternatively immediately fed back to the coating station, to beapplied again with the coating, in this manner circulating endlessaccording to the method of the instant invention.

The present invention pertains also to a device for performing themethod producing products in web form according to the transfer method.The device comprises at least a coating station, a laminating or coolingstation, separating rolls and a regeneration station for a transfersupport web, whereby the transfer support web is performed as an endlessloop.

The device in its preferred embodiment is illustrated for the skilledartisan by means of the attached drawing.

FIG. 1 shows, schematically, a machine of the present invention in sideview.

Especially, FIG. 1 shows the coating station 1, wherein the coating isapplied onto the transfer support web, and the heating device 2, whereinthe transfer support web coated with the coating is thermally treated.The heat treated transfer support web applied with the coating reach atthe point “A” the lamination station comprising a big cooling drum 3.Simultaneously, an intermediate support material coming from a storageroll 8 is laminated with the coating at point “A”. Before reaching point“A”, the support layer is fixed with a strip of an adhesive “B”, Afterthe cooling drum 3, separating rolls 4, 5, 6 and 7 are arranged. At thelast separating roll 7 the transfer support web is separated from theproduct in web form. The product in web form comprising the intermediatesupport amterial and the coating is fed to a winding station (notshown), whereas the transfer support web reaches the regenerationstation 9 where mechanical treatment and vacuum cleaning occurs. Therecirculation of the regenerated transfer support web to the coatingstation 1 is shown in the right part of the picture, whereas thealternative of winding up and using again of the transfer support web isnot illustrated in the picture.

The present invention is a novel and economic method to produce productsin web form, especially under cost saving conditions, since a minimum ofwaste material is caused due to the recirculation of the transfersupport web. According to the prior praxis, all used transfer supportweb had to be disposed of as waste material.

1. A method for producing products in web form comprising (i) first applying coating onto a surface of a transfer support web, (ii) subsequently drying the composite of transfer support web and coating, (iii) adjusting the humidity of the dried composite of transfer support web and coating to about 20 to 60%, (iv) then applying an intermediate support material on the coating of the humidity adjusted composite mentioned in step (iii) above, (v) finally separating the composite of intermediate support layer and humidity adjusted coating from the transfer support web, and (vi) winding up and storing the composite of intermediate support layer and coating, wherein the application of the intermediate support material as defined in step (iv) is carried out by feeding said humidity adjusted composite, comprising the coating and the transfer support web, to a cooling station, where said intermediate support material coming from a storage roll is applied onto the coating of said composite.
 2. A method according to claim 1, wherein the transfer support web comprises a solid material selected from (i) a polymer material, (ii) a composite material of paper with a polymer layer, (iii) a metal foil, or (iv) a composite material of metal and polymer film.
 3. A method according to claim 1, wherein the transfer support web has a uniform thickness over its total length.
 4. A method according to claim 1 wherein the coating is prepared by mixing its ingredients in an aqueous medium.
 5. A method according to claim 1, wherein the coating is applied to the transfer support web in a coating station by a casting method or a reverse coating method in, a thickness in the range of from 10 to 500 μm.
 6. A method according to claim 1, wherein the drying is performed in a hot air chamber at temperatures in the range of from 40 to 120° C.
 7. A method according to claim 6 wherein the drying is performed at temperatures in the range of from 50 to 100° C.
 8. A method according to claim 1, wherein the intermediate support material is fixed with a strip of an adhesive.
 9. A method according to claim 1, wherein the intermediate support material comprises paper, cardboard, or polymer film.
 10. A method according to claim 1, wherein the separated transfer support web is fed to a regeneration station, wherein regeneration of the transfer support web is performed.
 11. A method according to claim 10, wherein the regeneration of the transfer support web comprises at least mechanical treatment and vacuum cleaning of the mechanically treated transfer support web.
 12. A method according to claim 11, wherein the regeneration is combined with a wet or chemical decontamination comprising washing the transfer film with clear water or organic solvent or cleaning it with detergents and drying it in hot air.
 13. A method according to claim 10, wherein the regenerated transfer support web is immediately recirculated to the coating station, to be applied again with the coating.
 14. A method according to claim 10, wherein the regenerated transfer support web is first wound up and after storage recirculated again to the coating station, to be applied again with the coating.
 15. A method for producing products according to claim 1, wherein the coating comprises organic raw materials.
 16. A method for producing products according to claim 15, wherein the organic raw material is selected from polyvinyl alcohol, polyvinyl pyrrolidone, a cellulose derivative, polyvinyl acetate, polyethylene glycol, alginate, carrageenan, xanthan, gelatin, mixtures thereof or copolymers thereof. 